Optical discs (or recording media) such as a DVD and a Blu-ray disc have been rapidly spread. In such optical discs, various technologies have been suggested for OPC (Optimum Power Control) which appropriately adjusts a power of a laser beam (specifically, a recording power). For example, a patent document 1 discloses a technology of running OPC which corrects the power, as occasion demands, during the recording of a data pattern in order to compensate for deterioration of recording properties caused by variation in the recording sensitivity of an optical disc.    Patent document 1: Japanese Patent Application Laid Open No. 2006-120208